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Research for New Regulation: UCMR3
Massachusetts Water Resources Authority

The US Environmental Protection Agency (EPA) periodically requires water systems across the country to conduct monitoring for substances that may be present in drinking water to help understand their national occurrence as part of the process of deciding whether to regulate them.  Under the Safe Drinking Water Act Amendments, EPA established the Unregulated Contaminant Monitoring Rule and is required once every five years to develop a list of up to 30 new contaminants that must be monitored during a three year period by public water systems that meet the criteria for sampling.  This monitoring is used by EPA to understand the frequency and level of occurrence of unregulated contaminants in the nation’s public water systems (PWSs).

EPA will collect and analyze data for all three years and from systems all across the country to develop an understanding of the occurrence, level and distribution of these substances in drinking water. That data, along with information on potential halth effects and water treatment effectiveness will be used by EPA to determine if any new regulations are needed.

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UCMR 3 (2013-2015)

MWRA collected samples during 2013, 2014, and 2015 at locations throughout our service area for 21 contaminants and for 7 hormones. Even with the extremely sensitive test methods used capable of detecting some substances at parts per trillion levels, we expected to find very few of the substances that we were required to test for due to MWRA’s highly protected watershed and reservoirs. Only 5 of the 21 substances tested for in 2013, 2014, and 2015 were detected, and all were at extremely low levels. None of the seven hormones tested for in 2014 and 2015 were detected.

Here is a list of the UCMR 3 contaminants:

Contaminants (21)
1,2,3-trichloropropane  strontium
bromomethane  total chromium
chloromethane hexavalent chromium
bromochloromethane chlorate
chlorodifluoromethane perfluorooctanesulfonic acid
1,3-butadiene perfluorooctanoic acid
1,1-dichloroethane perfluorobutanesulfonic acid
1,4-dioxane perfluorohexanesulfonic acid
vanadium perfluoroheptanoic acid
molybdenum perfluorononanoic acid

Hormones (7)
17-a-Ethynylestradiol 17-b-Estradiol
Estrone 4-androstene-3,17-dione
Estriol Equilin

More information on these substances and UCMR3 can be found at at on the US EPA web site.

UCMR 3 Test Results

UCMR 3 (2013-2015) monitoring is complete.

MWRA UCMR 3 Test Results (2013-2015)
Fully Supplied Communities Partially Supplied Communities Chicopee Valley Aqueduct (CVA)
Results Below




South Hadley FD 1
Needham Wilbraham



Only these five substances discussed below were detected. All other substances listed in the UCMR3 were not detected. Note:  ppb = parts per billion = ug/L.    

Substance Measurement Units Average Range
Total Chromium  parts per billion (ppb)   0.23 0.2 - 0.35
EPA already regulates total chromium with a Maximum Contaminant Level (MCL) of 100 ppb and a Maximum Contaminant Level Goal of 0.  It is found at low levels in most water as it is an abundant element in the Earth’s crust.  MWRA regularly tests for it and does not detect it with the normally required detection limit of 1 ppb.  Total chromium was included in the UCMR3 testing with a more sensitive detection level to help understand hexavalent chromium occurrence data.  Results for total chromium were all below the normal detection limit, and far below the MCL of 100 ppb. 

Substance Measurement Units Average Range
Hexavalent Chromium  parts per billion (ppb) 0.04 ND - 0.13
Hexavalent chromium is one form of chromium.  It is not currently regulated by EPA, by Massachusetts, or any state other than California.  In June 2014, California issued a maximum contaminant level standard of 10 ppb.  It is commonly found in the environment, from both natural and human-made sources.  MWRA levels are well below this California standard. 

Substance Measurement Units Average Range
Chlorate  parts per billion (ppb) 116 32 - 307
Chlorate is a byproduct of disinfection with chlorine, and is commonly found in most waters in the US that use chlorine.  EPA and Massachusetts do regulate a number of disinfection by-products, and MWRA is well below those standards, but chlorate is not regulated at this time.  The World Health Organization has a provisional guideline value of 700 ppb, Health Canada has a guideline value of 1,000 ppb, and several years ago California proposed a standard (which was never finalized) of 500 ppb. EPA has not set a standard but has a provisional safe reference dose of 210 ppb for lifetime exposure.  MWRA levels are below all of these proposed or finalized standards. 

Substance Measurement Units Average Range
Strontium    parts per million (ppm) 0.04 0.03-0.05
Strontium is a metal that is common in nature, and small amounts are found in air, dust, soil, foods, and drinking water, though it is more commonly found at higher levels in ground water.   EPA has developed a non-regulatory lifetime health advisory of 4 ppm for strontium levels in drinking water.  MWRA levels are well below this health advisory. 

Substance Measurement Units Average Range
Vanadium parts per billion (ppb) 0.23 ND - 0.3
Vanadium is a naturally occurring “rare earth” element that is found ubiquitously in the earth’s crust. There are no federal or state standards, though California has proposed a Notification Level of 15 ppb. MWRA levels are well below this proposed Notification Level.

Updated May 5, 2022

Historic Withdrawls Reservoir Levels